This study examined the impact of differential-maternal parenting behavior, evaluated as a family-level experience, on children's emotional-behavioral problems. Data come from 3 child development studies: 2,128 four- to sixteen-year-olds (Ontario Child Health Study), 7,392 four- to eleven-year-olds (National Longitudinal Study of Children and Youth), and 1,992 three- to fourteen-year-olds (National Longitudinal Study of Youth). In 2 of 3 studies, there was consistent evidence that differential-maternal parenting behavior had an adverse impact on all siblings as a group, over and above parenting directed at individual siblings. The strength of association was sensitive to the type of maternal parenting behavior, dimension of child maladjustment, and respondent perspective (stronger for hostile/negative parenting, child externalizing problems, and mother assessments of child emotional-behavioral problems).